Tracking Device

ABSTRACT

A tracking device is disclosed for a unit, in particular a solar collector, to be directed toward a moving object. The tracking device has a bracket, which carries the unit and which is accommodated on a shaft that can be rotated about an azimuth axis by means of a hydraulic azimuth drive. Furthermore, the tracking device has a hydraulically adjustable tilting device for tilting the bracket, wherein a support of the shaft and the azimuth drive are arranged on or in a housing. At least one section of the shaft having the support thereof, the azimuth drive, and a pressure medium tank having pressure medium for supplying the azimuth drive and the tilting device are arranged in a common cavity of the housing.

The invention relates to a tracking device in accordance with the preamble of patent claim 1.

The publication DE 100 22 236 B4 shows a hydraulically driven, two-axis tracking device of this kind for a solar panel, in which the hydraulically driven actuators are mounted on the head of a mast. A miniature hydraulic unit with a tank integrated therein supplies the actuators with hydraulic oil. A support bracket for the solar panel is mounted within the mast head so as to be rotatable about a vertical azimuth axis. A bearing housing is filled with bearing oil, which is separated from the hydraulic oil by seals.

The disadvantage with tracking devices of this kind is the outlay for the separate lubrication of the various rolling contact bearings and of the rack of the azimuth adjustment system, which is provided by grease in an upper region and by an oil bath underneath, the latter being separated from the hydraulic oil.

Given this situation, it is the underlying object of the invention to provide a tracking device in which the outlay in terms of apparatus and maintenance is reduced.

This object is achieved by means of a tracking device as claimed in patent claim 1.

The tracking device according to the invention for a unit, in particular a solar collector, to be directed toward a moving object, has a bracket, which carries the unit and which is mounted on a shaft that can be rotated about an azimuth axis by means of a hydraulic azimuth drive. The tracking device furthermore has a hydraulically adjustable tilting device for tilting the bracket, wherein a bearing assembly of the shaft and the azimuth drive are arranged on or in a housing. In this arrangement, at least one section of the shaft with the bearing assembly thereof and a pressure medium tank containing pressure medium for supplying the azimuth drive and the tilting device are arranged in a common cavity of the housing. Since the pressure medium (hydraulic oil) lubricates the bearing assembly, the outlay in terms of apparatus and maintenance for the tracking device according to the invention is reduced.

Further advantageous embodiments of the invention are described in the dependent patent claims.

In a preferred development, the azimuth drive has a worm gear, which is arranged in the housing and the worm of which meshes with a worm wheel arranged on the shaft, wherein the worm is driven by means of a hydraulic motor. Since the pressure medium (hydraulic oil) lubricates the worm gear, there is a further reduction in the outlay in terms of apparatus and maintenance.

In a preferred development, the hydraulic motor is an axial piston motor, which is secured on an outer wall of the housing and the hydraulic ports of which are arranged on an end facing the housing.

In this case, the worm can be formed on a worm spindle which is accessible on both sides of the housing and on the first end section of which the hydraulic motor is arranged and on the second end section of which a rotational speed sensor is arranged. The latter is preferably a potentiometer, by means of which a high resolution and an absolute angle indication can be achieved at low cost.

In a particularly preferred development, the tilting device has a hydraulic cylinder, which engages on the bracket and engages directly or indirectly on the shaft and which can be supplied with pressure medium by means of a hydraulic pump arranged on the housing.

For the sake of a compact construction of the tracking device according to the invention, the azimuth drive, like the tilting device, is preferably also supplied by means of the hydraulic pump and an electric motor, which drives the hydraulic pump.

The electric motor can be a robust synchronous motor and the hydraulic pump can be a gear pump, both of which are placed against the housing in a radial direction with respect to the shaft.

In order to shorten or even completely eliminate piping, a tank port and a pressure port can be arranged on a side of the gear pump which faces the housing.

If a lateral wall section of the housing simultaneously forms a wall of the gear pump, one end wall of the gear pump can be omitted. If the tank port and the pressure port are through holes in the wall section, no piping is required for this purpose.

A preferred development has a control block with an electronic control unit and/or valves for controlling the supply to the azimuth drive and the tilting device.

The mounting of the bracket on the shaft is simplified if the shaft has a section which projects from the housing (toward the bracket).

The control block can be arranged adjacent to the projecting section of the shaft on an upper side of the housing, said upper side facing the bracket, or can be arranged laterally on the housing or in the housing. The latter integration offers particular protection from external influences.

In order to protect the pressure medium in the cavity of the housing from contamination, it is preferred if a dirt seal, which rests against the shaft, is fitted on the housing.

In order to maximize the cavity or tank volume, at least the section of the shaft which is accommodated in the housing can be made hollow.

Preference is given to a bearing assembly of the shaft with an axial bearing for supporting the weight of the bracket and of the unit and with a radial bearing, wherein the axial bearing is arranged between the radial bearing and the bracket. According to the invention, both bearings are immersed in the pressure medium in order to minimize friction.

For the sake of simple manufacture and assembly, the housing can be a casting, through the upper side of which the shaft can be inserted and on the underside of which, which faces away from the bracket, there is arranged an opening, through which the axial bearing and the radial bearing can be inserted. The opening on the underside can be closed by a housing cover. A casting of this kind can be machined before assembly, in particular to provide for the two bearing seats, the dirt seal and the bearing area for the housing cover.

In a development, the shaft carries a pivot bearing of the bracket, and the pivot of the pivot bearing lies in a radial plane of the shaft.

An embodiment of the invention is described in detail below with reference to the figures, in which:

FIG. 1 shows an embodiment of a tracking device according to the invention in a side view;

FIG. 2 shows the embodiment of the tracking device according to the invention in a section from the side; and

FIG. 3 shows the azimuth drive of the embodiment of the tracking device according to the invention in a sectioned plan view.

FIG. 1 shows an embodiment of a tracking device according to the invention for a flat solar collector or solar panel 12 in a side view. An approximately cuboidal housing 2 is mounted on a mast 1, of which only the upper end section is shown in FIG. 1. Projecting from the upper side 4 of said housing is a shaft 6, to the upper end of which a pivot bearing 8 is welded. By means of the pivot bearing 8, which has a pivot perpendicular to the plane of the drawing, the shaft 6 is connected to a bracket 10. The solar panel 12 is secured on the side of the bracket 10 which is at the top (FIG. 1), and the intention is to align and adjust the large-area upper side 14 of said panel perpendicularly to the sun. For this purpose, the shaft 6 is mounted so as to be rotatable about a vertical azimuth axis 16, taking the solar panel 12 along during a rotary motion by means of the pivot bearing 8 and the bracket 10. By means of this rotary motion, the solar panel 12 can follow a movement of the sun from east to west.

The tracking device can follow the vertical direction of movement of the sun by tilting the solar panel 12 about the pivot bearing 8, assuming the position illustrated in broken lines in FIG. 1, for example. A hydraulic cylinder 18 is provided for this tilting movement, said cylinder being attached pivotably to the shaft 6 by means of a joint 20, on the one hand, and to an edge section of the bracket 10 or of the solar panel 12 by means of a joint 22, on the other hand. The edge section can be lowered by retracting a piston rod 24, while the edge section can be raised (into the position shown in FIG. 1, for example) by extending the piston rod 24.

The rotation of the shaft 6 about the azimuth axis 16 is accomplished by means of a hydraulic motor 26 and of an azimuth drive, which is explained with reference to FIGS. 2 and 3.

Both hydraulic actuators 18, 26 are supplied with pressure medium by means of a gear pump 30 driven by a synchronous motor 28. A control block 32, which has an electronic control unit and valves for controlling and supplying pressure medium to the two actuators 18, 26, is furthermore arranged on the upper side 4 of the housing 2.

FIG. 2 shows the embodiment in accordance with FIG. 1 in a section from the side. The shaft 6 is embodied as a hollow shaft and has a circumferential section 34 which is stepped back radially at a step 40, on which section an axial bearing 36 and a radial bearing 38 are arranged. By means of these two bearings 36, 38, the shaft 6 and hence the solar panel 12 are mounted so as to be rotatable about the azimuth axis, wherein the shaft 6 is supported relative to the housing 2 along the azimuth axis 16 by means of the step 40 on the shaft, the axial bearing 36, a sleeve 42, an outer bearing ring of the radial bearing 38 and a housing cover 44. The housing cover 44 is secured and sealed off on an underside of the housing 2 by means of screws.

A cavity, which serves as the tank T of the tracking device, is provided within the housing 2 and the shaft 4. The hydraulic oil contained therein is drawn in by gearwheels 46, 48 of the gear pump 30 via a tank port 49 and is delivered to the hydraulic cylinder 18 and/or to the hydraulic motor 26 (neither of which is shown in FIG. 2) via a pressure port 51 and via valves of the control block 32.

An annular dirt seal 53, which rests against the shaft 6 and protects the pressure medium in the tank T from contamination, is inserted into an encircling recess on the upper side 4 of the housing 2.

The hydraulic motor 26 drives a worm 50, which imparts rotation, via a worm wheel 52, to the shaft 6 attached thereto. The worm wheel 52 is secured on the circumferential section 34 of the shaft 6 between the two bearings 36, 38.

FIG. 3 shows the azimuth drive of the embodiment in accordance with FIG. 1 and FIG. 2 in a sectioned plan view. The hollow shaft 6 is driven by the hydraulic motor 26 by means of a worm spindle 54, the worm 50 secured thereon and the worm wheel 52 meshing therewith. The worm spindle 54 is supported in a through aperture 60 in the housing 2 by means of two rolling contact bearings 56, 58. The worm spindle 54 is stepped back radially in the region of the bearings 56, 58, while the through aperture 60 is widened radially in the region of the bearings 56, 58. The rolling contact bearings 56, 58 can thus each be inserted into the through aperture 60 in the housing 2 from outside (from above and below in FIG. 3) during the assembly of the tracking device according to the invention. On one side (at the bottom in FIG. 2), the through aperture 60 is closed by the hydraulic motor 26, while a potentiometer 62 is arranged on the other side (the upper side in FIG. 3) of the through aperture 60, said potentiometer serving as a rotational speed sensor or rotational position sensor for the worm spindle 54, the worm 50 and the hydraulic motor 26.

A disclosure is made of a tracking device for a unit, in particular a solar collector, to be directed toward a moving object, which device has a bracket, which carries the unit and which is mounted on a shaft that can be rotated about an azimuth axis by means of a hydraulic azimuth drive. The tracking device furthermore has a hydraulically adjustable tilting device for tilting the bracket, wherein a bearing assembly of the shaft and the azimuth drive are arranged on or in a housing. At least one section of the shaft and the bearing assembly thereof, the azimuth drive and a pressure medium tank containing pressure medium for supplying the azimuth drive and the tilting device are arranged in a common cavity of the housing.

LIST OF REFERENCE SIGNS

1 mast

2 housing

4 upper side

6 shaft

8 pivot bearing

10 bracket

12 solar panel

14 upper side

16 azimuth axis

18 hydraulic cylinder

20, 22 joint

24 piston rod

26 hydraulic motor

28 synchronous motor

30 gear pump

32 control block

34 circumferential section

36 axial bearing

38 radial bearing

40 step

42 sleeve

44 housing cover

46, 48 gearwheel

49 tank port

50 worm

51 pressure port

52 worm wheel

53 dirt seal

54 worm spindle

56, 58 rolling contact bearing

60 through aperture

62 potentiometer

T tank 

1. A tracking device for a unit to be directed toward a moving object, comprising: a hydraulic azimuth drive; a shaft having a bearing assembly, the shaft being configured to be rotated about an azimuth axis by the hydraulic azimuth drive; a bracket which carries the unit and which is mounted on the shaft; a hydraulically adjustable tilting device configured to tilt the bracket; a housing defining a cavity; and a pressure medium tank configured to contain pressure medium for supplying the azimuth drive, wherein the bearing assembly of the shaft and the azimuth drive are arranged on or in the housing, and wherein at least one section of the shaft and the bearing assembly thereof, and the pressure medium tank and the tilting device are arranged in the cavity of the housing.
 2. The tracking device as claimed in patent claim 1, wherein the azimuth drive has a worm gear, which is arranged in the housing and the worm of of the worm gear meshes with a worm wheel arranged on the shaft, wherein the worm is driven by a hydraulic motor.
 3. The tracking device as claimed in patent claim 2, wherein the hydraulic motor is an axial piston motor, which is secured on an outer wall of the housing and the hydraulic ports of which are arranged on an end facing the housing.
 4. The tracking device as claimed in patent claim 2, wherein the worm is formed on a worm spindle which is accessible on both sides of the housing and on the first end section of which the hydraulic motor is arranged and on the second end section of which a rotational speed sensor is arranged.
 5. The tracking device as claimed in patent claim 1, wherein the tilting device has a hydraulic cylinder, which engages on the bracket and engages directly or indirectly on the shaft and which is configured to be supplied with pressure medium by a hydraulic pump arranged on the housing.
 6. The tracking device as claimed in patent claim 5, wherein the azimuth drive is supplied by the hydraulic pump and an electric motor, which drives the hydraulic pump.
 7. The tracking device as claimed in patent claim 6, wherein the electric motor is a synchronous motor, and the hydraulic pump is a gear pump, both of which are placed against the housing in a radial direction with respect to the shaft.
 8. The tracking device as claimed in patent claim 7, wherein a tank port and a pressure port are arranged on a side of the gear pump which faces the housing.
 9. The tracking device as claimed in patent claim 8, wherein a lateral wall section of the housing forms a wall of the gear pump, and wherein the tank port and the pressure port are through holes in the wall section.
 10. The tracking device as claimed in claim 1 further having a control block with an electronic control unit and/or valves for controlling the supply to the azimuth drive and the tilting device.
 11. The tracking device as claimed in claim 1, wherein the shaft has a section which projects from the housing toward the bracket.
 12. The tracking device as claimed in patent claim 10, wherein the control block is arranged adjacent to the projecting section of the shaft on an upper side of the housing, said upper side facing the bracket, or is arranged laterally on the housing or in the housing.
 13. The tracking device as claimed in patent claim 1, further comprising a dirt seal, which rests against the shaft, and is fitted on the housing.
 14. The tracking device as claimed in patent claim 1, wherein at least the section of the shaft which is accommodated in the housing is hollow.
 15. The tracking device as claimed in patent claim 1, wherein the bearing assembly of the shaft has an axial bearing and a radial bearing, wherein the axial bearing is arranged between the radial bearing and the bracket, and wherein both bearings are immersed in the pressure medium.
 16. The tracking device as claimed in patent claim 15, wherein the housing is a casting, through the upper side of which the shaft can be inserted and on the underside of which, which faces away from the bracket, there is arranged an opening, through which the axial bearing and the radial bearing can be inserted and which can be closed by a housing cover.
 17. The tracking device as claimed in patent claim 1, wherein the shaft carries a pivot bearing of the bracket, and wherein the pivot of the pivot bearing lies in a radial plane of the shaft.
 18. The tracking device as claimed in claim 4, wherein the rotational speed sensor is a potentiometer.
 19. The tracking device as claimed in claim 1, wherein the unit is a solar collector. 